Angled tip catheter

ABSTRACT

A catheter having improved ability to cross body passage obstructions and that more easily allows backloading of a guidewire into the lumen of the catheter is comprised of a tip, a shaft, and a lumen. The distal end of the catheter tip is oriented at an angle other than 90° to the lengthwise axis of the catheter tip. A guidewire may be easily backloaded into the elongated catheter lumen at the location of the angled catheter tip.

This application is a continuation of application Ser. No. 13/314,441,filed Dec. 8, 0211, which is continuation of application Ser. No.12/355,327, filed Jan. 16, 2009, which claims the benefit of U.S.Provisional Application No. 61/021,947, filed Jan. 18, 2008, entitled“Angled Tip Catheter”, the contents of each of which are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to catheters for advancement to a site ina body. More particularly, this invention pertains to a catheter foradvancement across an obstruction in a body passage.

BACKGROUND OF THE INVENTION

Catheters are commonly used for advancement into a body passage forpurposes such as diagnosis or treatment of medical conditions. Examplesof such passages include but are not limited to a carotid artery,coronary artery, femoral artery, other blood vessel, a ureter, urethra,bronchus, esophagus, or other passage. Examples of such cathetersinclude but are not limited to diagnostic, guide, balloon (PTCA, PTNA orPTA), stent delivery (BES, SES or DES), drug delivery, infusion,aspiration, atherectomy, thrombectomy, embolic protection devicedelivery, embolic protection device recovery, and others. Such cathetersare typically used by first advancing a guidewire into the body passage,backloading the proximal end of the guidewire into the distal end of acatheter lumen, and advancing the catheter over the guidewire to aregion of interest.

It is not unusual for the body passage to be partially obstructed due toatherosclerotic disease, tumors, mechanical causes (May-Thurnerssyndrome), or other causes. Advancing catheters past the obstruction canbe difficult and time consuming. Part of the problem is that inconventional catheters there is generally not a smooth transition fromthe guidewire outer diameter to the catheter outer diameter. Themismatch between said diameters becomes an impediment to successfulcatheter advancement across an obstruction.

There are some catheters in the market addressing the problem ofadvancement past an obstruction but they are generally expensive andtheir results are operator dependent. For example, steerable cathetershave been tried, as well as laser catheters and blunt dissectors. Bothof these latter approaches carry a risk of perforation of the passagewall, and ablative technologies generate potentially harmful ablatedmaterials.

Another problem encountered with these catheters is that the backloadingof guidewires into catheter lumens can be difficult due to dim lightingin most catheterization labs and farsightedness of older practitioners.There have been some accessory devices marketed to simplify the processof backloading guidewires into catheter lumens but none have seenwidespread adoption in the market.

What is needed is a catheter having improved ability to cross bodypassage obstructions and a catheter that more easily allows backloadingof a guidewire into the lumen of the catheter.

SUMMARY OF THE INVENTION

The invention provides a catheter having improved ability to cross bodypassage obstructions and that more easily allows backloading of aguidewire into the lumen of the catheter is comprised of a tip, a shaft,and a lumen. The distal end of the catheter tip is oriented at an angleother than 90° to the lengthwise axis of the catheter tip. A guidewiremay be easily backloaded into the elongated catheter lumen at thelocation of the angled catheter tip. The catheter shaft hascharacteristics that facilitate orienting the tip angle relative to abody passage obstruction.

The invention provides a catheter comprising an elongate shaft, a distaltip, and a lumen extending proximally from the distal tip, a firstdistal end of the distal tip being oriented at a first angle other than90 degrees to the lengthwise axis of the catheter tip, a second distalend of the distal tip being oriented at a second angle other than 90degrees to the lengthwise axis of the catheter tip, the second distalend of the distal tip being adjacent to the first distal end of thedistal tip, the second distal end of the distal tip being proximal ofthe first distal end of the distal tip, and the second angle being lessthan the first angle.

The invention provides a catheter comprising an elongate shaft having alength, a distal tip, and a lumen extending proximally from the distaltip, a distal end of the distal tip being oriented at an angle otherthan 90 degrees to the lengthwise axis of the catheter tip, and theshaft having a length and the shaft having a bend at least from thedistal tip to a point 10 percent of the shaft length proximal from thedistal tip.

The invention provides a catheter comprising an elongate shaft, a distaltip, and a lumen extending proximally from the distal tip, a distal endof the distal tip being oriented at an angle other than 90 degrees tothe lengthwise axis of the catheter tip, the distal tip comprising atapered region, and the catheter being a balloon catheter.

The invention provides an assembly comprising a guidewire and a catheterdescribed herein. The invention provides a method of advancing acatheter into a body lumen of a patient comprising: loading a guidewireinto the lumen of a catheter of described herein; advancing theguidewire into the body lumen; and advancing the catheter over theguidewire into the body lumen.

It is to be understood that that both the foregoing general descriptionand the following detailed description are exemplary and explanatory andare intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of the invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings.

FIG. 1 illustrates a side elevation view of an embodiment of a catheterhaving features in accordance with the principles of the presentdisclosure.

FIG. 2 illustrates a side elevation view of a prior art catheter tip.

FIGS. 3A and 3B illustrate side elevation views of embodiments ofcatheter tips having features in accordance with the principles of thepresent disclosure, with a conventional guidewire shown in phantom line.

FIG. 4 illustrates a plan view of the catheter tip illustrated in FIG.3A having features in accordance with the principles of the presentdisclosure.

FIG. 5 illustrates a side elevation view of an alternative embodiment ofa catheter having features in accordance with the principles of thepresent disclosure.

FIGS. 6A, 6B, and 6C illustrate use of a catheter and conventionalguidewire in a body passage in accordance with the principles of thepresent disclosure.

DETAILED DESCRIPTION

The invention provides a catheter comprising an elongate shaft, a distaltip, and a lumen extending proximally from the distal tip, a firstdistal end of the distal tip being oriented at a first angle other than90 degrees to the lengthwise axis of the catheter tip, a second distalend of the distal tip being oriented at a second angle other than 90degrees to the lengthwise axis of the catheter tip, the second distalend of the distal tip being adjacent to the first distal end of thedistal tip, the second distal end of the distal tip being proximal ofthe first distal end of the distal tip, and the second angle being lessthan the first angle. In an embodiment, the first angle is from 70degrees to 20 degrees. In another embodiment, the first angle isselected from the group consisting of 65, 60, 55, 50, 45, 40, 35, or 30degrees. In an embodiment, the second angle is from 60 to 10 degrees. Inanother embodiment, the second angle is selected from the groupconsisting of 55, 50, 45, 40, 35, 30, 25, or 20 degrees. In anembodiment, the first angle is 65 degrees and the second angle is 55degrees. In another embodiment, the second angle is 5 to 20 degrees lessthan the first angle. In an embodiment, the second angle is 10 degreesless than the first angle.

In an embodiment, the shaft has a length of 10 cm to 300 cm. In anotherembodiment, the shaft has a length of 20 cm. In an embodiment, thedistal tip comprises a tapered region. In another embodiment, thetapered region has an angle relative to the lengthwise axis of thecatheter tip of 1 to 16 degrees. In an embodiment, the distal tip has alength of 2 mm to 12 mm. In an embodiment, the lumen extends proximallyfrom the distal end of the distal tip. In another embodiment, the lumenextends proximally from the distal end of the distal tip to a proximalend of the shaft.

In an embodiment, the shaft has a length and the shaft has a bend overat least some of its length. In another embodiment, the shaft has a bendover all of its length. In an embodiment, the shaft has a bend at leastfrom the distal tip to a midpoint of the shaft. In another embodiment,the shaft has a bend at least from the distal tip to a point 25 percentof the shaft length proximal from the distal tip. In an embodiment, theshaft has a bend at least from the distal tip to a point 10 percent ofthe shaft length proximal from the distal tip. In an embodiment, theshaft has a maximum concavity of from 0.2 cm to 2 cm as measured over alength of 10 cm. In another embodiment, the shaft has a maximumconcavity selected from the group consisting of 0.4 cm, 0.6 cm, 0.8 cm,1.0 cm, 1.2 cm, 1.4 cm, 1.6 cm, and 1.8 cm. In an embodiment, the shafthas a maximum concavity of 0.4 cm. In an embodiment, the catheter is aballoon catheter.

The invention provides a catheter comprising an elongate shaft having alength, a distal tip, and a lumen extending proximally from the distaltip, a distal end of the distal tip being oriented at an angle otherthan 90 degrees to the lengthwise axis of the catheter tip, and theshaft having a length and the shaft having a bend at least from thedistal tip to a point 10 percent of the shaft length proximal from thedistal tip. In an embodiment, the shaft has a bend over all of itslength. In another embodiment, the shaft has a bend at least from thedistal tip to a midpoint of the shaft. In an embodiment, the shaft has abend at least from the distal tip to a point 25 percent of the shaftlength proximal from the distal tip. In an embodiment, the shaft has amaximum concavity of from 0.2 cm to 2 cm as measured over a length of 10cm. In another embodiment, the shaft has a maximum concavity selectedfrom the group consisting of 0.4 cm, 0.6 cm, 0.8 cm, 1.0 cm, 1.2 cm, 1.4cm, 1.6 cm, and 1.8 cm. In an embodiment, the shaft has a maximumconcavity of 0.4 cm.

In an embodiment, the angle is from 70 degrees to 20 degrees. In anotherembodiment, the angle is selected from the group consisting of 65, 60,55, 50, 45, 40, 35, and 30 degrees. In an embodiment, the shaft has alength of 10 cm to 300 cm. In an embodiment, the shaft has a length of20 cm. In an embodiment, the distal tip comprises a tapered region. Inanother embodiment, the tapered region has an angle relative to thelengthwise axis of the catheter tip of 1 to 16 degrees. In anembodiment, the distal tip has a length of 2 mm to 12 mm. In anembodiment, the lumen extends proximally from the distal end of thedistal tip. In another embodiment, the lumen extends proximally from thedistal end of the distal tip to a proximal end of the shaft. In anembodiment, the catheter is a balloon catheter.

The invention provides a catheter comprising an elongate shaft, a distaltip, and a lumen extending proximally from the distal tip, a distal endof the distal tip being oriented at an angle other than 90 degrees tothe lengthwise axis of the catheter tip, the distal tip comprising atapered region, and the catheter being a balloon catheter. In anembodiment, the angle is from 70 degrees to 20 degrees. In anotherembodiment, the angle is selected from the group consisting of 65, 60,55, 50, 45, 40, 35, and 30 degrees. In an embodiment, the shaft has alength of 10 cm to 300 cm. In another embodiment, the shaft has a lengthof 20 cm. In an embodiment, the tapered region has an angle relative tothe lengthwise axis of the catheter tip of 1 to 16 degrees. In anembodiment, the distal tip has a length of 2 mm to 12 mm. In anembodiment, the lumen extends proximally from the distal end of thedistal tip. In another embodiment, the lumen extends proximally from thedistal end of the distal tip to a proximal end of the shaft.

The invention provides an assembly comprising a guidewire and a catheterdescribed herein.

The invention provides a method of advancing a catheter into a bodylumen of a patient comprising: providing a catheter, the cathetercomprising an elongate shaft, a distal tip, and a lumen extendingproximally from the distal tip, a first distal end of the distal tipbeing oriented at a first angle other than 90 degrees to the lengthwiseaxis of the catheter tip, a second distal end of the distal tip beingoriented at a second angle other than 90 degrees to the lengthwise axisof the catheter tip, the second distal end of the distal tip beingadjacent to the first distal end of the distal tip, the second distalend of the distal tip being proximal of the first distal end of thedistal tip, and the second angle being less than the first angle;loading a guidewire into the lumen of the catheter; advancing theguidewire into the body lumen; and advancing the catheter over theguidewire into the body lumen. In an embodiment, the catheter traversesan obstruction in the body lumen. In another embodiment, the body lumenis a blood vessel. In an embodiment, the shaft has a length, the shafthas a bend over at least some of its length, and the shaft has a maximumconcavity of 0.2 cm to 2 cm as measured over a length of 10 cm, andwherein the catheter self-orients on the guidewire such that the maximumconcavity is aligned with a maximum convex curvature of the guidewire.In another embodiment, the guidewire is advanced into the body lumensuch that it traverses an obstruction in the body lumen, the guidewirehaving a bend at a portion of the guidewire that traverses theobstruction, the bend creating a gap between the guidewire and theobstruction, the method further comprising orienting a distal mostportion of the distal tip so that the distal most portion of the distaltip traverses the obstruction through the gap as the catheter traversesthe obstruction. In an embodiment, the orienting of the distal mostportion of the distal tip occurs because the catheter self-orients onthe guidewire. In an embodiment, the catheter is a balloon catheter.

The invention provides a method of advancing a catheter into a bodylumen of a patient comprising: providing a catheter, the cathetercomprising an elongate shaft having a length, a distal tip, and a lumenextending proximally from the distal tip, a distal end of the distal tipbeing oriented at an angle other than 90 degrees to the lengthwise axisof the catheter tip, and the shaft having a length and the shaft havinga bend at least from the distal tip to a point 10 percent of the shaftlength proximal from the distal tip; loading a guidewire into the lumenof the catheter; advancing the guidewire into the body lumen; andadvancing the catheter over the guidewire into the body lumen. In anembodiment, the catheter traverses an obstruction in the body lumen. Inanother embodiment, the body lumen is a blood vessel. In an embodiment,the shaft has a maximum concavity of 0.2 cm to 2 cm as measured over alength of 10 cm, and wherein the catheter self-orients on the guidewiresuch that the maximum concavity is aligned with a maximum convexcurvature of the guidewire. In an embodiment, the guidewire is advancedinto the body lumen such that it traverses an obstruction in the bodylumen, the guidewire having a bend at a portion of the guidewire thattraverses the obstruction, the bend creating a gap between the guidewireand the obstruction, the method further comprising orienting a distalmost portion of the distal tip so that the distal most portion of thedistal tip traverses the obstruction through the gap as the cathetertraverses the obstruction. In an embodiment, the orienting of the distalmost portion of the distal tip occurs because the catheter self-orientson the guidewire. In an embodiment, the catheter is a balloon catheter.

The invention provides a method of advancing a catheter into a bodylumen of a patient comprising: providing a catheter, the cathetercomprising an elongate shaft, a distal tip, and a lumen extendingproximally from the distal tip, a distal end of the distal tip beingoriented at an angle other than 90 degrees to the lengthwise axis of thecatheter tip, the distal tip comprising a tapered region, and thecatheter being a balloon catheter; loading a guidewire into the lumen ofthe catheter; advancing the guidewire into the body lumen; and advancingthe catheter over the guidewire into the body lumen. In an embodiment,the catheter traverses an obstruction in the body lumen. In anotherembodiment, the body lumen is a blood vessel. In an embodiment, theguidewire is advanced into the body lumen such that it traverses anobstruction in the body lumen, the guidewire having a bend at a portionof the guidewire that traverses the obstruction, the bend creating a gapbetween the guidewire and the obstruction, the method further comprisingorienting a distal most portion of the distal tip so that the distalmost portion of the distal tip traverses the obstruction through the gapas the catheter traverses the obstruction.

With reference now to the various drawing figures, a description isprovided of embodiments that are examples of how inventive aspects inaccordance with the principles of the present invention may bepracticed. It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory only and are not restrictive of the broad inventive aspectsdisclosed herein. It will also be appreciated that the inventiveconcepts disclosed herein are not limited to the particular deviceconfigurations disclosed herein, but are instead applicable to anynumber of different device configurations.

FIG. 1 illustrates catheter 10 having hub 12, shaft 14, lumen 16 and tip18. Hub 12 may be comprised of a luer fitting made of polycarbonate orsimilar materials, and may be configured for attachment to a syringe(not shown) or extension tube (not shown) for administration of fluidsinto a patient, aspiration of substances from a patient, or monitoring acondition (e.g., pressure) within a patient. Hub 12 is attached to shaft14 using methods such as adhesive bonding or insert molding as are knownin the art. Shaft 14 may be comprised of materials such as nylon,polybutylene terephthalate-long chain polyether glycols block copolymersuch as HYTREL® polymer, polyether block amide such as PEBAX® polymer,polyethylene, polyimide, metal, polyurethane, or other materials and maybe reinforced with braid, coils, fillers, or other substances. In oneembodiment shaft 14 is a nylon extruded tube comprising stainless steelbraided wire. Shafts having a length of 10 cm to 300 cm arecontemplated. In one embodiment, shaft 14 has a length of 20 cm. Inother embodiments, shaft 14 has a length of 30 cm, 40 cm, 60 cm, 80 cm,120 cm, 160 cm, 200 cm, or 250 cm. Shaft outside diameters of 2 Fr (0.07cm) to 10 Fr (0.33 cm) are contemplated. In one embodiment, shaft 14 hasan outside diameter of 2.5 Fr (0.085 cm). In other embodiments, shaft 14has outside diameters of 3 Fr (0.1 cm), 4 Fr (0.13 cm), 5 Fr (0.17 cm),6 Fr (0.2 cm), 7 Fr (0.23 cm), 8 Fr (0.27 cm), or 9 Fr (0.3 cm). Lumen16 slidably accommodates a guidewire (including hostwires or otherwires). Guidewires having a length of 20 cm to 320 cm are contemplated,and guidewires having diameters of 0.009″ (0.023 cm) to 0.063″ (0.16 cm)are contemplated. In one embodiment, lumen 16 accommodates a guidewirehaving a diameter of 0.010″ (0.025 cm). In other embodiments, lumen 16accommodates a guidewire having a diameter of 0.014″ (0.036 cm), 0.018″(0.046 cm), 0.021″ (0.053 cm), 0.025″ (0.064 cm), 0.035″ (0.089 cm),0.038″ (0.097 cm), or 0.063″ (0.16 cm).

Shaft 14 may also comprise a balloon, stent, cutter, diagnostic sensor(e.g., temperature, pressure, pO₂), or other diagnostic or therapeuticportion, generally mounted to the distal region of the shaft. Shaft 14may comprise one or more additional lumens, a distal region moreflexible than a proximal region, radiopaque marker bands, or radiopaquefillers.

Tip 18 is shown in further detail in FIGS. 3A and 3B with guidewire GWshown in phantom line, and in FIG. 4. For comparison purposes a priorart catheter tip is shown in FIG. 2 with guidewire GW shown in phantomline.

Tip 18 a in FIG. 3A is comprised of tapered region 32 and end 34. Lumen16 extends through the tip. Tip lengths of 2 mm to 12 mm arecontemplated, and the tip may be comprised of polyether block amide suchas PEBAX® polymer, polyurethane, styrene-ethylene-butylene-styrene blockcopolymer such as C-FLEX® polymer, nylon, or other materials and may bemanufactured by insert molding, welding, reflow methods, or othermethods as are known in the art. Tip 18 a may comprise radiopaquematerials to show the orientation of distal most tip 31 underfluoroscopy. For example, longitudinal stripes of radiopaque filler ormaterials may be incorporated into tip 18 a sidewall using extrusiontechniques known in the art. Tapered region 32 is formed having angle 37relative to axis A-A of tip 18. Angles 37 of 1° to 16° are contemplated.In one embodiment, angle 37 is 1.5°. In other embodiments, angle 37 is2°, 4°, 6°, 8°, 10°, 12°, or 14°. In still other embodiments, region 32is not tapered. End 34 has distal most tip 31, is oriented at primaryangle 38 relative to longitudinal axis A-A of tip 18, and may be sooriented by molding, cutting, laser cutting, or other methods. Distalmost tip 31 may be rounded or otherwise softened to prevent causingdamage to body passages during use. Angles 38 of 70° to 20° arecontemplated. In one embodiment, angle 38 is 65°. In other embodiments,angle 38 is 60°, 55°, 50°, 45°, 40°, 35°, or 30°.

Tip 18 b in FIG. 3B is comprised of tapered region 32 and ends 34 a, 34b. Lumen 16 extends through tip. Tip lengths of 2 mm to 20 mm arecontemplated, and tip may be comprised of polyether block amide such asPEBAX® polymer, polyurethane, styrene-ethylene-butylene-styrene blockcopolymer such as C-FLEX® polymer, nylon, or other materials and may bemanufactured by insert molding, welding, reflow methods, or othermethods as are known in the art. Tip 18 b may comprise radiopaquematerials to show the orientation of distal most tip 31 underfluoroscopy. For example, longitudinal stripes of radiopaque filler ormaterials may be incorporated into tip 18 b sidewall using extrusiontechniques known in the art. Tapered region 32 is formed having angle 37relative to axis A-A of tip 18 b. Angles 37 of 1° to 16° arecontemplated. In one embodiment, angle 37 is 1.5°. In other embodiments,angle 37 is 2°, 4°, 6°, 8°, 10°, 12°, or 14°. In still otherembodiments, region 32 is not tapered. End 34 a has distal most tip 31and is oriented at primary angle 38 relative to axis A-A of tip 18.Distal most tip 31 may be rounded or otherwise softened to preventcausing damage to body passages during use. End 34 b is oriented atsecondary angle 39 relative to axis A-A of tip 18. Secondary angle 39 isless than primary angle 38. Ends 34 a, 34 b may be so oriented bymolding, cutting, laser cutting, or other methods. Primary angles 38 of70° to 20° are contemplated. In one embodiment, primary angle 38 is 65°.In other embodiments, primary angle 38 is 60°, 55°, 50°, 45°, 40°, 35°,or 30°. Secondary angles 39 of 60° to 10° are contemplated. In oneembodiment, secondary angle 39 is 55°. In other embodiments, secondaryangle 39 is 50°, 45°, 40°, 35°, 30°, 25°, or 20°.

FIG. 4 shows a plan view of tip 18 a. For illustration purposes the tipof FIG. 3A having a primary angle and no secondary angle is shown. It isunderstood that the tip of FIG. 3B, comprised of both a primary and asecondary angle, will also have a length L of exposed lumen 16. Becauseend 34 of tip 18 a is formed at angle 38 a length L of lumen 16 isexposed to the exterior surface of catheter 10 through sidewall opening42. In contrast, prior art catheters 20 (FIG. 2) having tip 22 have nosuch exposed length or sidewall opening because end 24 of tip 22 isformed at angle 28 of approximately 90° relative to axis C-C of catheter20. A guidewire GW can be more easily backloaded into lumen 16 ofcatheter 10 through sidewall opening 42 and distal opening of lumen 16than backloading a guidewire GW into distal opening (only) of the lumenin prior art catheter 20. This is because the combined distal luminalopenings in catheter 10 are larger than the distal luminal opening inprior art catheter 20.

FIG. 5 illustrates an alternative embodiment of a catheter havingfeatures in accordance with the principles of the present invention.Catheter 50 is comprised of hub 52, shaft 54, lumen 56 and tip 58. Hub52, shaft 54, lumen 56 and tip 58 have substantially the same functionand are comprised of substantially the same materials as hub 12, shaft14, lumen 16, and tips 18 a, 18 b described above for catheter 10.Additionally, catheter 50 comprises a bend 59 over some or all of shaft54 length, thereby causing catheter 50 to have convex aspect 57 a andconcave aspect 57 b. Maximum concavity Y, measured over a length X of 10cm, in the range of 0.2 cm to 2 cm is contemplated. In one embodiment,maximum concavity Y is 0.4 cm. In other embodiments, maximum concavity Yis 0.6 cm, 0.8 cm, 1.0 cm, 1.2 cm, 1.4 cm, 1.6 cm, or 1.8 cm. ConcavityY causes catheter 50 to self-orient on a guidewire GW in a bend in abody passage such that maximum concavity Y will be aligned with themaximum convex curvature of guidewire GW.

An example of a method of using a catheter that more easily allowsbackloading of a guidewire into the lumen of the catheter and that hasimproved ability to cross body passage obstructions in a body of apatient is now described. Using techniques well known in the art,guidewire GW is percutaneously inserted into a patient's blood vesseland advanced to a region of interest in the patient's body. Usingimaging techniques such as fluoroscopy an obstructed portion of thevessel is identified and the tip of the guidewire is advanced across theobstruction. With reference to FIG. 4, proximal end of guidewire GW isbackloaded into tip 18 a, 18 b, 58 of catheter 10, 50 by placingproximal end of guidewire through opening 42 onto exposed length L oflumen 16, 56 and then sliding guidewire GW proximally into lumen 16, 56.

Catheter 10, 50 is advanced over guidewire GW to a position proximal tovessel V obstruction OB (FIG. 6A) using imaging techniques such asfluoroscopy. Tip 18 a, 18 b, 58 is oriented relative to obstruction OBsuch that distal most portion 31 of the tip is positioned at the insideof the bend (FIG. 6A). In this orientation gap 62 will be presentbetween wire GW and obstruction OB when catheter 10, 50 is being pushedacross obstruction. Catheter 10, 50 is then pushed to advance distalmost portion 31 across obstruction OB (FIG. 6B). Further pushing ofcatheter 10, 50 across obstruction will cause ends 34, 34 b to traverseobstruction OB (FIG. 6C). It is easier to cause ends 34, 34 b totraverse obstruction OB because they are at an angle to the catheteraxis, in comparison to prior art (FIG. 2) where end 24 is atapproximately 90° relative to axis C-C of the catheter forming a ledgeat 24 between guidewire GW and tip 22.

Once catheter 10, 50 has been advanced across obstruction OB the desireddiagnostic procedure, monitoring, or treatment can be performed.

In an alternative method guidewire GW is advanced while advancingcatheter 10, 50 across obstruction OB, to help assure presence of gap62.

In another method, tip 18 a, 18 b, 58 is oriented relative toobstruction OB such that distal most portion 31 of the tip is positionedat the outside of the bend and guidewire GW is retracted. Retraction ofguidewire GW causes gap 62 to form at the outside of the bend in vesselV. Catheter 10, 50 is then advanced across obstruction OB to cause tip18 a, 18 b, 58 to traverse obstruction.

In yet another method, catheter 10, 50 may be sequentially torqued,advanced, and withdrawn until the catheter tip is able to be advancedacross the obstruction. In this way multiple tip orientations relativeto the obstruction may be tried. In yet another method, catheter 10, 50may be torqued as it is advanced across obstruction OB.

In an alternative method suitable for body passages that are notstraight, catheter 50 is not torqued to orient the catheter tip relativeto the obstruction, rather the catheter is allowed to self orient in thebend.

The above description and the drawings are provided for the purpose ofdescribing embodiments of the invention and are not intended to limitthe scope of the invention in any way. It will be apparent to thoseskilled in the art that various modifications and variations can be madewithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. Further, while choices formaterials and configurations may have been described above with respectto certain embodiments, one of ordinary skill in the art will understandthat the materials and configurations described are applicable acrossthe embodiments.

What is claimed is:
 1. A method of advancing a catheter into a bloodvessel of a patient comprising: providing a catheter, the cathetercomprising an elongate shaft having proximal and distal ends, a lengthextending between the proximal and distal ends, a distal tip having alengthwise axis and defining the distal end of the shaft, a distalopening defined by the distal end of the shaft, and a lumen extendingproximally from the distal opening through the proximal end of theshaft, wherein an entirety of the distal end of the shaft is oriented atan angle other than 90 degrees to the lengthwise axis of the distal tip,and wherein the shaft has a bend from the distal tip to a location thatis at least 10 percent of the shaft length proximal from the distal tip,wherein the bend of the shaft has a maximum concavity of 0.2 cm to 2 cmas measured over a length of 10 cm; advancing a guidewire into a bloodvessel of a subject, wherein the guidewire has a bend having a maximumconvex curvature, wherein said advancing a guidewire into a blood vesselcomprises traversing an obstruction in the blood vessel with theguidewire such that the bend of the guidewire traverses the obstructionand a pap is created between the bend of the guidewire and theobstruction; backloading the guidewire through the distal opening andinto the lumen of the shaft; advancing the catheter over the guidewireand into the blood vessel, wherein said advancing the catheter over theguidewire comprises traversing the obstruction with the distal tip ofthe shaft, after said traversing the obstruction with the guidewire; andself-orienting the shaft on the guidewire as the catheter is advancedover the guidewire such that the maximum concavity of the shaft isaligned with the maximum convex curvature of the guidewire.
 2. Themethod set forth in claim 1 , further comprising performing treatment inthe blood vessel using the catheter, after said traversing theobstruction with the distal tip of the shaft.
 3. The method set forth inclaim 1 , wherein said advancing the catheter over the guidewirecomprises advancing the shaft of the catheter to a position where thedistal tip of the shaft is adjacent and proximal the obstruction, beforesaid traversing the obstruction with the distal tip of the shaft, themethod further comprising orienting a distal most portion of the distaltip of the shaft so that the distal most portion is positioned at aninside of the bend of the guidewire, after said advancing the shaft to aposition where the distal tip of the shaft is adjacent and proximal theobstruction and before said traversing the obstruction with the distaltip of the shaft.
 4. The method set forth in claim 3, further comprisingperforming treatment in the blood vessel using the catheter, after saidtraversing the obstruction with the distal tip of the shaft.
 5. Themethod set forth in claim 1, wherein said advancing the catheter overthe guidewire comprises advancing the shaft of the catheter to aposition where the distal tip of the shaft is adjacent and proximal theobstruction, before said traversing the obstruction with the distal tipof the shaft, the method further comprising orienting a distal mostportion of the distal tip of the shaft so that the distal most portionis positioned at an outside of the bend of the guidewire, after saidadvancing the shaft to a position where the distal tip of the shaft isadjacent and proximal the obstruction and before said traversing theobstruction with the distal tip of the shaft.
 6. The method set forth inclaim 5, further comprising retracting the guidewire so that a gapbetween the obstruction and the guidewire is formed at the outside ofthe bend of the guidewire, after the said orienting a distal mostportion of the distal tip of the shaft, wherein said traversing theobstruction with the distal tip of the shaft is performed after saidretracting the guidewire.
 7. The method set forth in claim 6, furthercomprising performing treatment in the blood vessel using the catheter,after said traversing the obstruction with the distal tip of the shaft.